1. Field of the Invention
The present invention relates to a photosensitive composition used in a process of manufacturing a semiconductor device, or the like, and a pattern formation method using the photosensitive composition.
2. Description of the Related Art
As the integration and speed of LSI increase, the miniaturization of the pattern rule is quickly progressing. As the leading edge of miniaturization technology, an ArF immersion lithography is used for mass-production of semiconductor devices. As a lithography technology of the next-generation, an extreme-ultraviolet (EUV) lithography with a wavelength of 13.5 nm and the like are further researched and developed.
In recent years, with progress of the miniaturization of patterns, the thickness of the resist, which is a photosensitive composition used for pattern formation, is reduced. Therefore, when etching is carried out on an underlying layer using a micro-patterned resist as a mask, such a drawback arises prominently that the etching resistance of the resist is insufficient. In order to reinforce the etching resistance of this resist, various resist materials containing metal oxides having resistance to etching are examined.
However, the resist materials containing metal oxides entail a drawback of low storage stability or low coating stability. The drawback of low coating stability is created as follows. That is, when a resist solution is applied by spin-coating on a wafer and dried by heat to form a resist film, the characteristics of the film varies before the pattern is drawn. In other words, there is a dependency on the post-coating delay (PCD) time, and therefore the sensitivity of the resist at pattern exposure varies. The conventional resists containing metal oxides have insufficient storage stability. Unlike general-use silicon-containing compositions, a metal oxide with the skeleton of a transition metal may act to change the molecular structure in the composition when stored for long time. If such a resist solution is used, a pattern defect may likely be created during the manufacture of semiconductor devices.